Methods and devices for switching a virtual internet protocol address

ABSTRACT

Methods and devices for switching a virtual internet protocol (VIP) address are provided. In one implementation, the method may include sending to a control center of a VIP address system a first address resolution protocol (ARP) mapping message for mapping a VIP address to a VM address of a virtual machine (VM) of the VIP address system. The control center may be configured to determine the VM corresponding to the VM address as the master VM using the VIP address. The VIP address system may include one or more VMs connected to one or more virtual switches, the one or more VMs and one or more virtual switches being located in one or more hosts that are connected to the control center via a cloud network. The method may further include sending a notification message from the control center determining the master VM to a VM in the VIP address system.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and benefits of Chinese PatentApplication Serial No. 201611238096.0, filed with the State IntellectualProperty Office of P. R. China on Dec. 28, 2016, which is incorporatedherein by reference in its entirety.

BACKGROUND

In a physical network of existing technologies, a floating InternetProtocol (IP) address is a shared virtual IP address used for serverswitching in a dual-host server backup circumstance. Using the floatingIP address, an application end may not detect the switch of the IPaddress of the local host server. When the IP address floats to aphysical server, the physical server may declare the floating IP addressas using the Address Resolution Protocol (ARP), and provide services viathe floating IP address. However, the range the floating IP address mayreach is limited by the number of ports of the physical servers, andtypically does not go beyond one hundred physical servers.

In a cloud network, a virtual internet protocol (VIP) address used by aphysical server is allocated and managed by a virtualization platform.However, the virtualization platform does not allow for IP floatingamong Virtual Machines (VMs). Cloud network applications or software,such as Keepalived and Heartbeat, may only run normally when the hostservers have the ability to switch using a floating IP. Therefore, torun these applications or software in a cloud network, their softwarecodes would need to be modified.

SUMMARY

The embodiments of present application provide methods and devices forswitching a VIP address. The methods and devices may advantageouslysolve the problem of IP address floating among Virtual Machines (VMs)that cannot be achieved in the existing cloud network, thereby allowingfor the running of high availability applications or software in theexisting cloud network.

In some embodiments, the present disclosure provides a method forswitching a virtual internet protocol (VIP) address. The method mayinclude sending to a control center of a VIP address system a firstaddress resolution protocol (ARP) mapping message for mapping a VIPaddress to a VM address of a virtual machine (VM) of the VIP addresssystem. The control center is configured to determine the VMcorresponding to the VM address as the master VM using the VIP address.The VIP address system may include one or more VMs connected to one ormore virtual switches, the one or more VMs and one or more virtualswitches being located in one or more hosts that are connected to thecontrol center via a cloud network. The method may further includesending a notification message to a VM in the VIP address system. Thenotification message is from the control centerdetermining the masterVM.

In some embodiments, the present disclosure provides a method forswitching a virtual internet protocol (VIP) address. The method mayinclude receiving, from a virtual switch, a first ARP mapping messagefor mapping a VIP address to a virtual machine (VM) of a VIP addresssystem using the VIP address. The VIP address system may include one ormore VMs connected to one or more virtual switches, the one or more VMsand one or more virtual switches being located in one or more hosts. Themethod may further include determining the VM as the master VM based onthe first ARP mapping message; and sending a notification message ofdetermining the master VM to a VM in the VIP address system via thevirtual switch connected to the VM.

In some embodiments, the present disclosure provides a non-transitorycomputer readable medium that stores a set of instructions that isexecutable by at least one processor of a server to cause the server toperform a method for switching a virtual internet protocol (VIP)address. The method may include providing for sending to a controlcenter of a VIP address system a first address resolution protocol (ARP)mapping message for mapping a VIP address to a VM address of a virtualmachine (VM) of the VIP address system. The control center is configuredto determine the VM corresponding to the VM address as the master VMusing the VIP address. The VIP address system may include one or moreVMs connected to one or more virtual switches, the one or more VMs andone or more virtual switches being located in one or more hostsconnected to the control center via a cloud network. The method mayfurther include providing for sending a notification message from thecontrol center determining the master VM to a VM in the VIP addresssystem.

In some embodiments, the present disclosure provides a non-transitorycomputer readable medium that stores a set of instructions that isexecutable by at least one processor of a server to cause the server toperform a method for switching a virtual internet protocol (VIP)address. The method may include acquiring, from a virtual switch, afirst ARP mapping message for mapping a VIP address to a virtual machine(VM) of a VIP address system using the VIP address. The VIP addresssystem may include one or more VMs connected to one or more virtualswitches, the one or more VMs and one or more virtual switches beinglocated in one or more hosts. The method may further includedetermining, based on the first ARP mapping message, the VM as themaster VM; and providing for sending, via the virtual switch, anotification message of determining the master VM to a VM in the VIPaddress system.

In some embodiments, the present disclosure provides a virtual internetprotocol (VIP) address switching apparatus. The apparatus may include afirst sending unit configured to send to a control center of a VIPaddress system a first address resolution protocol (ARP) mapping messagefor mapping a VIP address to a VM address of a virtual machine (VM) ofthe VIP address system. The VIP address system may include one or moreVMs connected to one or more virtual switches, the one or more VMs andone or more virtual switches being located in one or more hosts that areconnected to the control center via a cloud network. VIP address may beused by the control center to determine the VM corresponding to the VMaddress as the master VM. The apparatus may further include a secondsending unit configured to send a notification message to a VM in theVIP address system. The notification message is from the control centerdetermining the master VM.

In some embodiments, the present disclosure provides a virtual internetprotocol (VIP) address system. The system may include a control center,and at least one host connected to the control center via a cloudnetwork, the at least one host being provided with a virtual machine(VM) and a virtual switch connected to the VM. The virtual switch isconfigured to send to the control center an ARP mapping message formapping a VIP address to a VM address of a VM. The control center isconfigured to receive the ARP mapping message from the virtual switch,determine, based on the ARP mapping message, the VM as the master VM,and send, via the virtual switch, the notification message ofdetermining the master VM to a VM in the VIP address system.

In accordance with the technical solutions provided by the presentdisclosure, a virtual switch sends to a control center a first ARPmapping message for mapping a VIP address to a VM address of a VM of aVIP address system. This allows the control center to determine a VMcorresponding to the VM address as the master VM using the VIP addressand the other VMs as backup VMs. The control center may return, via avirtual switch, an identifier of the master VM by carrying theidentifier in a notification message to a VM connected to the virtualswitch, thereby facilitating the forwarding of data associated with theVIP address to the master VM. In this way, an ARP request can beprocessed in the VIP address system based on a cloud network, the VIPaddress floating in the cloud network can be achieved, and VRRR (VirtualRouter Redundancy Protocol)-based software with high availability, suchas Keepalived and Heartbeat, can be used.

Additional features and advantages of the disclosed embodiments will beset forth in part in the description that follows, and in part will beobvious from the description, or may be learned by practice of thedisclosed embodiments. The features and advantages of the disclosedembodiments will be realized and attained by the elements andcombinations particularly pointed out in the appended claims.

It is to be understood that both the foregoing general description andthe following detailed description are examples and explanatory only andare not restrictive of the disclosed embodiments as claimed.

The accompanying drawings constitute a part of this specification. Thedrawings illustrate several embodiments of the present disclosure and,together with the description, serve to explain the principles of thedisclosed embodiments as set forth in the accompanying claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings constitute a part of this specification. Thedrawings illustrate several embodiments of the present disclosure and,together with the description, serve to explain the principles of thedisclosure.

FIG. 1 is a schematic diagram illustrating an exemplary architecture forswitching a virtual internet protocol address, consistent withembodiments of the present disclosure.

FIG. 2 is a flow chart of an exemplary method for switching a virtualinternet protocol address, consistent with embodiments of the presentdisclosure.

FIG. 3 is a flow chart of an exemplary method for switching a virtualinternet protocol address, consistent with embodiments of the presentdisclosure.

FIG. 4 is a schematic diagram illustrating the hardware structure of anexemplary device for switching a virtual internet protocol address,consistent with embodiments of the present disclosure.

FIG. 5 is a schematic diagram illustrating the hardware structure of anexemplary device for switching a virtual internet protocol address,consistent with embodiments of the present disclosure.

FIG. 6 is a schematic block diagram of an exemplary apparatus forswitching a virtual internet protocol address, consistent withembodiments of the present disclosure.

FIG. 7 is a schematic block diagram of an exemplary apparatus forswitching a virtual internet protocol address, consistent withembodiments of the present disclosure.

DETAILED DESCRIPTION

Reference will now be made in detail to embodiments and aspects of thepresent disclosure, examples of which are illustrated in theaccompanying drawings. Where possible, the same reference numbers willbe used throughout the drawings to refer to the same or like parts.

In existing techniques, an IP address in a virtual network can appearunchanged to the outside using a Software Load Balancer scheme. In thisscheme, it is assumed that there are a first virtual machine (VM 1)having an address of IP 1 and a second virtual machine (VM 2) having anaddress of IP 2. Currently, the VM 1 is the master VM. The Software LoadBalancer uses a mapping relationship between a VIP and the IP 1. TheSoftware Load Balancer thus currently presents to the outside that theVIP is the serving IP address. When the VM 1 is detected to be abnormal,an Application Programming Interface (API) of the Software Load Balanceris called to change the mapping relationship between the VIP and the IPaddress. For example, the mapping relationship can be modified as amapping relationship between the VIP and the IP 2 such that the standbyVM2 at the back end is switched to be the master VM while the IP addresspresented to the outside remains the VIP address, unchanged. In thisscheme, the Software Load Balancer does not perform IP address floating.When the master VM is abnormal, the Software Load Balancer needs tomodify the mapping relationship between the VIP and the IP address of aVM so that the IP address presented to the outside can remain unchanged.In addition, since the Software Load Balancer is designed based on afour-layer Transmission Control Protocol (TCP) or User Datagram Protocol(UDP), it is not suitable for two-layer or three-layer networkarchitecture, which limits the use of the Software Load Balancer.

Therefore, the embodiments of the present disclosure provide methods anddevices for switching a VIP address in a cloud network system. Themethods and devices allow for the connection of a control center withone more host servers associated with one or more VMs and virtualswitches via a message transmission channel of the cloud network,thereby constructing a cloud network-based VIP address system. In anexemplary VIP address system, a virtual switch sends to the controlcenter a first ARP mapping message received by the VM for mapping a VIPaddress to a VM address. This allows the control center to determine theVM corresponding to the VM address as the master VM using the VIPaddress and to determine other VMs as backup VMs. The control centerreturns an identifier of the master VM by carrying the identifier in anotification message sent to each VM in the VIP address system via thevirtual switch. This in turn facilitates the forwarding of dataassociated with the VIP address to the master VM. In this way, an ARPrequest can be processed and the IP address floating in the cloudnetwork can be achieved without conducting any control over or amendingthe relationship between the master and backup VMs. Thus, the presentdisclosure solve the problems of existing techniques, such as notperforming IP address floating in a cloud network, being only applicableto four- or more-layer network protocols, etc.

As described herein, the embodiments consistent with the presentdisclosure can be applied to an exemplary server. The exemplary servercan be a physical or logical server. Various functions of the exemplarycan also be achieved by cooperation between two or more physical orlogical servers that take on different responsibilities. Any suitabletype of server, and any suitable type and protocol of the communicationnetwork between servers, etc., may be used by embodiments of the presentdisclosure.

FIG. 1 a schematic diagram illustrating an exemplary architecture forswitching a VIP address, consistent with embodiments of the presentdisclosure. As shown in FIG. 1, the architecture is herein referred toas a VIP address system 100, which may include: a control center 102, amessage transmission channel 104 based on a cloud network connected tocontrol center 102, and several hosts or host servers 105-107 connectedto message transmission channel 104, wherein each host is provided witha virtual switch (e.g., virtual switch 110 of host 105) and a VM (e.g.,virtual machine 112 of host 105) connected to the virtual switch. Inthis exemplary architecture, the IP address used by each VM is the sameVIP address, but the VIP address can only be used by one VM at one time,and cannot be used by two or more VMs at the same time. Control center102 can be a server, and there may be, for example, hundreds ofthousands of hosts connected to the message transmission channel.

FIG. 2 is a flow chart of an exemplary method 200 for switching a VIPaddress, consistent with embodiments of the present disclosure. Method200 can be performed by a virtual switch, such as virtual switch 110 ofFIG. 1. As shown in FIG. 2, method 200 may include steps 201 and 202.

In step 201, the virtual switch receives a first ARP mapping message formapping a VIP address to a VM address and sends the first ARP mappingmessage to a control center (e.g., control center 102 of FIG. 1). Thecontrol center determines a VM corresponding to the VM address as themaster VM using the VIP address.

Among various VMs in a VIP address system, a certain VM can send, whenusing a VIP address, an ARP request to a virtual switch connected to theVM. The virtual switch receives the ARP request, and sends to a controlcenter an ARP mapping message for mapping the VIP address to the VM. TheARP mapping message may carry an identifier of a host where the VM islocated, such as an IP address of the host. The ARP mapping message mayalso carry the IP address of the VM, and may further carry the VIPaddress currently used by the VM. After receiving the mapping message,the control center determines the VM currently using the VIP address asthe master VM for processing the ARP request. Then, the control centerrecords an identifier of the VM currently using the VIP address, such asthe IP address of the VM and the IP address of the host where the VM islocated.

In step 202, one or more virtual switches send a notification messagefrom the control center determining the master VM to their correspondingVMs in the VIP address system such that data associated with the VIPaddress is forwarded to the master VM.

In some embodiments, the virtual switches each can send to theircorresponding VMs a notification message from the control center forindicating an identifier of the master VM currently using the VIPaddress. Accordingly, after receiving the notification message, each VMmay determine whether the identifier in the notification message isconsistent with its own identifier. If the identifier in thenotification message is consistent with its own identifier, the VMdetermines that it is the master VM, and thus can use the VIP addressfor communication, and may process the received data associated with theVIP address, such as the ARP request. If the identifier in thenotification message is inconsistent with its own identifier, the VMdetermines that it is not the master VM, but a backup VM, and thus canrelease network resources occupied thereby and may not use the VIPaddress for communication. In such instances, the network resources canbe allocated to and used by the master VM, thereby improving the runningefficiency of the master VM and/or increasing the availability of thecloud network.

In some embodiments, the control center does not deliver thenotification message after recording an identifier of a VM currentlyusing the VIP address. Each VM autonomously sends, when needed or at aset time interval, a message acquisition request to the control centerto request to obtain an identifier of the VM currently using the VIPaddress, thereby pulling the information about the master VM. In suchinstances, a virtual switch corresponding to a VM may send to thecontrol center a request message sent by the VM for acquiring theidentifier of the master VM. Subsequently, the virtual switch canreceive a response message returned by the control center and carryingthe identifier of the master VM. The virtual switch then may send theresponse message to the VM, so that the VM determines whether it is themaster VM itself based on the master VM identifier. Accordingly, theconsumption of network resources can be reduced. The use of networkresources caused by the control center delivering the notificationmessage while the VM runs abnormally and cannot receive the notificationmessage can be reduced or avoided.

In the embodiments of the present application, only the VM that isdetermined by the control center as the master VM is responsible forusing the VIP address for communication with an external device, such asreceiving data associated with the VIP address, and responding to theARP request. All data associated with the VIP address can be forwardedto the master VM for processing.

When a VM determines that it is not the master VM itself, it can acquirean association relationship between its identifier and a priority levelto become the master VM, and thus can determine its priority forbecoming the master VM. In some embodiments, a backup VM with thehighest priority can monitor the health condition of the master VM, andswitch its address to the VIP address when the master VM is detected tobe abnormal, so as to facilitate or maintain normal communication. Abackup VM having a lower priority level can stay in an idle orsubstantially idle state, and can release network resources occupied forthe master VM to use, thereby improving and/or maintaining the runningefficiency of the master VM.

In some embodiments, each VM has a priority level that indicates theorder of each VM, when serving as a backup VM, to become the master VM.The priority level can be determined based on various factors, such asthe configuration of a VM and the configuration of a host where the VMis located. The association relationship between the identifier of a VMand its priority level can be stored in the control center, or in thecorresponding host. The process for acquiring a priority level mayinclude: the virtual switch sending to the control center a requestmessage sent by a backup VM for acquiring the association relationship;the virtual switch receiving the association relationship returned bythe control center; and the virtual switch sending the associationrelationship to the backup VM such that the backup VM can determine itsown priority level and/or order to become the master VM based on theassociation relationship.

In some embodiments, the backup VM that determines its priority level tobe the highest may detect the health condition of the master VM at a settime interval. For example, the backup VM with the highest prioritylevel can detect whether the master VM is abnormal, and can switch itsIP address to the VIP address to maintain normal communication when themaster VM is detected to be abnormal, such as when the master VM fails,when the host where the master VM is located fails, and at time ofnetwork failure.

In some embodiments, in the VIP address system, when the master VM isdetermined to be abnormal, the backup VM with the highest priority sendsa second ARP request to the virtual switch after executing the VIPaddress switch. However, packet loss may occur such that the virtualswitch may not receive the second ARP request, and thus does not knowthat the backup VM has switched to the VIP address. Therefore, thevirtual switch cannot second the second ARP request to the controlcenter, and the control center cannot update in time the recordedinformation of the master VM currently using the VIP address, which mayin turn affect the real-time performance of the IP address floating. Toreduce or avoid the occurrence of such a situation, the virtual switchcan regularly inspect the condition of a VM using the VIP address. Ifthe last inspection result is that the VIP address is not used by theVM, while the present inspection result is that the VIP address is beingused by the VM, the virtual switch can determine that an IP addressswitching has occurred, and that the VM has switched to the VIP address.If the last inspection result is that the VIP address was being used,while the present inspection result is that the VIP address is not beingused, the virtual switch can determine that an IP address switchoccurred, and the VIP address has been switched to another VM. In bothcircumstances, the virtual switch may send a message regarding theswitch to the control center in the form of an ARP mapping message sothat the control center can update in time the stored identifier of themaster VM, i.e., the IP address of the host where the master VM islocated and the IP address of the master VM. The virtual switch can alsoreceive a heartbeat message sent by a VM to determine whether a VIPaddress switch has occurred, and to determine whether to send an ARPmapping message to the control center.

In some embodiments, when the master VM is determined to be abnormal andthe backup VM with the highest priority is switched to the VIP address,a second ARP request is sent by the backup VM to the virtual switchconnected thereto. Based on the second ARP request, the virtual switchsends to the control center a second ARP mapping message for mapping theVIP address to the backup VM, the second ARP mapping message carryingthe IP address of the host where the backup VM is located, the IPaddress of the VM, and the VIP address. The control center receives thesecond ARP mapping message, determines the corresponding backup VM asthe master VM, and records an identifier of the new master VM. Then thevirtual switch may each send to its corresponding VM a notificationmessage from the control center that indicates the identifier of themaster VM currently using the VIP address. The original master VM thatwas abnormal can become a backup VM as well because it does not use theVIP address any more. Therefore, the control center determines the VMcurrently using the VIP address as the master VM.

In the embodiments consistent with the present disclosure, in anexemplary cloud network-based VIP address system, the virtual switchsends to the control center a first ARP mapping message received by a VMfor mapping a VIP address to a VM address. This allows the controlcenter to determine the VM corresponding to the VM address as the masterVM using the VIP address and to determine other VMs as backup VMs. Thecontrol center returns an identifier of the master VM by carrying theidentifier in a notification message sent to each VM in the VIP addresssystem via the virtual switch. This in turn facilitates the forwardingof data associated with the VIP address to the master VM. In this way,an ARP request can be processed and IP-address floating in the cloudnetwork can be achieved without conducting any control over or amendingthe relationship between the master and backup VMs, thereby allowing forthe convenient use of software with high availability, such asKeepalived and Heartbeat. In addition, the message transmission channelbased on a cloud network can be connected to hundreds of thousands ofhosts, which advantageously expands the range the floating VIP addresscan reach, comparing to about one hundred hosts connected in a physicalnetwork due to the limited number of ports.

FIG. 3 is a flow chart of an exemplary method 300 for switching avirtual internet protocol address, consistent with embodiments of thepresent disclosure. Method 300 can be performed by a control center,such as control center 102 of FIG. 1. Method 300 may include steps301-303.

In step 301, the control center receives from a virtual switch a firstARP mapping message for mapping a VIP address to a VM using the VIPaddress.

As described above with reference to FIG. 2, the VM using the VIPaddress may send to a control center a first ARP mapping message via avirtual switch connected thereto, the first ARP mapping message carryingthe IP address of a host where the VM is located, the IP address of theVM, and the VIP address.

In step 302, the control center determines the VM as the master VM basedon the first ARP mapping message.

In some embodiments, a VM corresponding to the first ARP mapping messagereceived by the control center is the VM currently using the VIPaddress. The control center records the IP address of the host and theIP address of the VM in the first ARP mapping message, and determinesthe VM currently using the VIP address as the master VM. Accordingly,other VMs in the VIP address system, i.e., VMs currently not using theVIP address, are backup VMs.

In step 303, the control center sends a notification message determiningthe master VM to one or more VMs in the VIP address system via one ormore virtual switches connected thereto such that data associated withthe VIP address is forwarded to the master VM.

As described above with reference to FIG. 2, the control center maydeliver to each VM a notification message for identifying an identifierof the master VM currently using the VIP address, and each VM may alsoactively acquire the identifier of the master VM from the controlcenter.

In some embodiments, the control center can also determine the prioritylevel of each VM to become the master VM based on the configuration ofeach VM, and may store an association relationship between the prioritylevel and the identifier of each VM. In this way, a VM, such as a backupVM, can acquire the association relationship from the control center,and thus acquire its own priority level and determine whether to monitorthe health condition of the master VM.

In some embodiments, when the master VM is determined to be abnormal,the control center allows the VIP address to remain unchanged during adisaster recovery switch process by determining a new master VM,achieving IP address floating in the cloud network, thereby improvingthe high availability of the VIP address system, and allowing forconvenient use of common high availability software, such as Keepalivedand Heartbeat, without the need to modify codes of such software. Inaddition, the use of an ARP protocol in embodiments of the presentdisclosure is applicable to two- and more-layer network architectures.

The embodiments of the present disclosure also provide exemplaryapparatuses and devices for switching a VIP address. The exemplaryapparatuses and devices may implement the exemplary methods describedabove. The structures of the exemplary apparatuses and devices aredescribed and illustrated below with reference to FIGS. 4-7.

In some embodiments, a control center may implement VIP addressswitching methods or apparatuses consistent with the present disclosure.Apparatus embodiments of the present disclosure may take the form of anentirely hardware embodiment, an entirely software embodiment, or anembodiment combining software and hardware. For an exemplary softwareembodiment, an apparatus may be a logical module of computer programinstructions stored in a non-volatile computer-readable storage medium,read into a memory, and executed by a processor of a device. The one ormore modules configured for execution on computing devices can beprovided on a non-transitory computer readable medium, such as a compactdisc, digital video disc, RAM, ROM, flash drive, or any othernon-transitory medium, or as a digital download (and can be originallystored in a compressed or installable format that requires installation,decompression, or decryption prior to execution). FIG. 4 is a schematicdiagram illustrating the hardware structure of an exemplary device 400for switching a VIP address, consistent with embodiments of the presentdisclosure. As shown in FIG. 4, device 400 for switching a VIP addressmay include a processor 410, a memory 420, a network interface 430, anda non-volatile computer-readable storage medium 450. An exemplary VIPaddress switching apparatus 440 implemented by a control center may be alogical module of computer program instructions that are stored innon-volatile computer-readable storage medium 450, read into memory 420,and executed by processor 410 of device 400. Device 400 where theapparatus 440 is located can further include other hardware componentsthat perform other functions of device 400 not shown in FIG. 4.

In some embodiments, a server may implement VIP address switchingmethods or apparatuses consistent with the present disclosure. Apparatusembodiments of the present disclosure may take the form of an entirelyhardware embodiment, an entirely software embodiment, or an embodimentcombining software and hardware. For an exemplary software embodiment,an apparatus may be a logical module of computer program instructionsstored in a non-volatile computer-readable storage medium, read into amemory, and executed by a processor of a device. The one or more modulesconfigured for execution on computing devices can be provided on anon-transitory computer readable medium, such as a compact disc, digitalvideo disc, RAM, ROM, flash drive, or any other non-transitory medium,or as a digital download (and can be originally stored in a compressedor installable format that requires installation, decompression, ordecryption prior to execution). FIG. 5 is a schematic diagramillustrating the hardware structure of an exemplary device 500 forswitching a VIP address, consistent with embodiments of the presentdisclosure. As shown in FIG. 5, device 500 for switching a VIP addressmay include a processor 510, a memory 520, a network interface 530, anda non-volatile computer-readable storage medium 540. An exemplary VIPaddress switching apparatus 540 implemented by a server may be a logicalmodule of computer program instructions that are stored in non-volatilecomputer-readable storage medium 550, read into memory 520, and executedby processor 510 of device 500. Device 500 where the apparatus 540 islocated can further include other hardware components that perform otherfunctions of device 500 not shown in FIG. 5.

FIG. 6 is a schematic block diagram of an exemplary apparatus 600 forswitching a VIP address, consistent with embodiments of the presentdisclosure. The exemplary apparatus can be implemented in a VIP addresssystem. As shown in FIG. 1, the VIP address system may include a controlcenter and several hosts connected to the control center via a cloudnetwork. Each host can be provided with a VM and a virtual switchconnected to the VM. Apparatus 600 can be implemented using one or moremodules/units (and any corresponding sub-modules/sub-units), which canbe a packaged functional hardware unit designed for use with othercomponents (e.g., portions of an integrated circuit) and/or a part of aprogram (stored on a computer readable medium, e.g. a non-volatilestorage medium) that performs a particular function of relatedfunctions. The one or more modules can have entry and exit points andcan be written in a programming language, such as, for example, Java,Lua, C, or C₊₊. A software module can be compiled and linked into anexecutable program, installed in a dynamic link library, or written inan interpreted programming language such as, for example, BASIC, Perl,or Python. It will be appreciated that software modules can be callablefrom other modules or from themselves, and/or can be invoked in responseto detected events or interrupts. Software modules configured forexecution on computing devices can be provided on a non-transitorycomputer readable medium, such as a compact disc, digital video disc,RAM, ROM, flash drive, or any other non-transitory medium, or as adigital download (and can be originally stored in a compressed orinstallable format that requires installation, decompression, ordecryption prior to execution). Software code can be stored, partiallyor fully, on a memory device of the executing computing device, forexecution by apparatus 600. Software instructions can be embedded infirmware, such as an EPROM. It will be further appreciated that hardwaremodules can be comprised of connected logic units, such as gates andflip-flops, and/or can be comprised of programmable units, such asprogrammable gate arrays or processors.

As shown in FIG. 6, apparatus 600 may include a first sending unit 610and a second sending unit 620. The first sending unit 610 is configuredto send to the control center a first ARP mapping message received froma VM for mapping a VIP address to a VM address. This allows the controlcenter to determine the VM corresponding to the VM address as the masterVM using the VIP address.

The second sending unit 620 is configured to send a notification messagefrom the control center determining the master VM to a VM in the VIPaddress system such that data associated with the VIP address isforwarded to the master VM. In some embodiments, the second sending unit620 may include a first receiving sub-unit. The first receiving sub-unitis configured to receive a notification message, sent by the controlcenter, for indicating an identifier of the master VM currently usingthe VIP address. In some embodiments, the second sending unit 620 mayfurther include a first sending sub-unit configured to send thenotification message to a VM in the VIP address system such that dataassociated with the VIP address can be forwarded to the master VM.

In some embodiments, apparatus 600 may further include a first receivingunit. The first receiving unit is configured to receive, when the masterVM is determined to be abnormal, a second ARP mapping message formapping the VIP address to the address of one backup VM (different fromthe master VM) sent by the backup VM after the backup VM switches its IFaddress to the VIP address.

In some embodiments, apparatus 600 may further include a third sendingunit configured to send the second ARP mapping message to the controlcenter such that the control center can determine that the backup VM asthe new master VM.

In some embodiments, apparatus 600 may further include a fourth sendingunit configured to send to the control center a request message, sent bya VM, for acquiring the master VM identifier, a second receiving unitconfigured to receive a response message returned by the control center,carrying the master VM identifier, and a first replying unit configuredto send the response message to the VM such that the VM determineswhether itself is the master VM based on the master VM identifier.

In some embodiments, apparatus 600 may further include a fifth sendingunit configured to send to the control center a request message, sent bya backup VM, for acquiring an association relationship; a thirdreceiving unit configured to receive the association relationshipreturned by the control center, indicating the priority level of thebackup VM to become the master VM and the identifier of the backup VM;and a sixth sending unit configured to send the association relationshipto the backup VM for the backup VM determines its own priority level tobecome the master VM.

In some embodiments, sixth sending unit is further configured to:detect, at a set time interval, whether the master VM is abnormal whenthe priority level of the backup VM to become the master VM is thehighest; and release occupied network resources when the priority levelof the backup VM to become the master VM is not the highest.

In some embodiments, apparatus 600 may further include a fourthreceiving unit configured to receive a heartbeat message sent by a VM;and a first determining unit configured to determine, based on theheartbeat message, whether the VIP address has switched and whether tosend a second ARP mapping message to the control center.

FIG. 7 is a schematic block diagram of an exemplary apparatus 700 forswitching a VIP address, consistent with embodiments of the presentdisclosure. The exemplary apparatus can be implemented in a VIP addresssystem. As shown in FIG. 1, the VIP address system may include a controlcenter and several hosts connected to the control center via a cloudnetwork, with each host being provided with a VM and a virtual switchconnected to the VM. Apparatus 700 may include one or more components ofapparatus 600 as described above with reference to FIG. 6. Apparatus may700 also include a fifth receiving unit 710, a second determining unit720, and a seventh sending unit 740.

Fifth receiving unit 710 is configured to receive, from a virtualswitch, an ARP mapping message for mapping a VIP address to a VM usingthe VIP address.

Second determining unit 720 is configured to determine, based on the ARPmapping message, the VM as the master VM.

Seventh sending unit 740 is configured to send, via the virtual switch,a notification message determining the master VM to a VM in the VIPaddress system such that data associated with the VIP address isforwarded to the master VM.

In some embodiments, apparatus 700 may further include a sixth receivingunit configured to receive a request message from a VM, sent via thevirtual switch, for acquiring the master VM identifier, and a secondreplying unit configured to send to the VM, via the virtual switch, aresponse message carrying the identifier of the master VM currentlyusing the VIP address based on the request message.

In some embodiments, apparatus 700 may further include a thirddetermining unit configured to determine the priority level of each VMto become the master VM based on the configuration of each VM in the VIPaddress; and a storing unit configured to store an associationrelationship between a priority level and an identifier of each VM.

In some embodiments, apparatus 700 may further include a seventhreceiving unit configured to receive a request message for acquiring theassociation relationship from a backup VM sent via the virtual switch,and a third replying unit configured to send the associationrelationship to the backup VM via the virtual switch.

In some embodiments, a VIP address system may implement the exemplarymethods described above. As shown in FIG. 1, an exemplary VIP addresssystem 100 consistent with the present application includes a controlcenter 102, at least one host (e.g., hosts 105-107) connected to thecontrol center via a cloud network, with the host being provided with aVM (e.g., VM 112) and a virtual switch (e.g., virtual switch 110)connected to the VM. The virtual switch is configured to send to controlcenter 102 an ARP mapping message for mapping a VIP address to a VMaddress received from the VM such that control center 102 can determinea VM corresponding to the VM address as the master VM using the VIPaddress. The virtual switch is further configured to send a notificationmessage determining the master VM from control center 102 to a VM in theVIP address system such that data associated with the VIP address isforwarded to the master VM. Control center is configured to receive theARP mapping message from the virtual switch. Based on the ARP mappingmessage, control center 102 is further configured to determine the VM asthe master. VM and send the notification message of determining themaster VM to a VM via the virtual switch.

Similar features and functions of the exemplary VIP address system andthe exemplary apparatuses consistent with embodiment of the presentdisclosure may be found in the description above for the exemplarymethods.

The apparatus embodiments described above are merely illustrative.Exemplary modules or units are described as separated components may ormay not be physically separated from each other. The exemplary units mayor may not be physical units, and may be positioned at one location ormay be distributed over multiple networks. One or more of the modules orunits may be selected according to practical requirements to achieve theobjectives of the solutions of the present disclosure. Similar solutionsimplemented consistent with embodiments of the present disclosure canalso be used.

Consistent with the embodiments of the present disclosure, a controlcenter determines, based on an ARP mapping message sent by a VM via acloud network, a VM currently using a VIP address as the master VM; anda backup VM automatically switches to the VIP address when the master VMis detected to be abnormal. Without the need to make amendments to thesoftware codes, the VIP address floating in the cloud network can beachieved, and VRRR-based software with high availability, such asKeepalived and Heartbeat, can be used. In addition, as shown in FIG. 1,the message transmission channel based on a cloud network can beconnected to hundreds of thousands of hosts, which expands the range ofthe VIP address floating. This is advantageous over a physical networkwhere about one hundred hosts can be connected in the physical networkdue to the limited number of ports.

The present disclosure may be described in a general context ofcomputer-executable commands or operations, such as a program module,stored on a computer readable medium and executed by a computing deviceor a computing system, including at least one of a microprocessor, aprocessor, a central processing unit (CPU), a graphical processing unit(GPU), etc. In general, the program module may include routines,procedures, objects, components, data structures, processors, memories,and the like for performing specific tasks or implementing a sequence ofsteps or operations.

The present disclosure may also be implemented in a distributedcomputing environment, and in these distributed computing environments,tasks or operations may be executed by a remote processing deviceconnected through a communication network, e.g., the Internet. In thedistributed computing environment, the program module may be located ina local or a remote non-transitory computer-readable storage medium,including a flash disk or other forms of flash memory, a Read-OnlyMemory (ROM), a Random Access Memory (RAM), a magnetic disk, an opticaldisk, a cache, a register, etc.

Furthermore, although aspects of the disclosed embodiments are describedas being associated with data and/or instructions stored in a memoryand/or other tangible and/or non-transitory computer-readable mediums,it would be appreciated that these data and/or instructions can also bestored on and executed from many types of tangible computer-readablestorage medium, such as storage devices, including hard disks, floppydisks, or CD-ROM, or other forms of RAM or ROM. Accordingly, thedisclosed embodiments are not limited to the above-described examples,but instead is defined by the appended claims in light of their fullscope of equivalents.

Embodiments of the present disclosure may be embodied as a method, asystem, a computer program product, etc. Accordingly, embodiments of thepresent disclosure may take the form of an entirely hardware embodiment,an entirely software embodiment, or an embodiment combining software andhardware for allowing a specialized device having the describedspecialized components to perform the functions described above.Furthermore, embodiments of the present disclosure may take the form ofa computer program product embodied in one or more computer-readablestorage media that may be used for storing computer-readable programcodes.

Embodiments of the present disclosure are described with reference toflow charts and/or block diagrams of methods, devices (systems), andcomputer program products. It will be understood that each flow chartand/or block diagram can be implemented by computer programinstructions. These computer program instructions may be provided to aprocessor of a special-purpose computer, an embedded processor, or otherprogrammable data processing devices or systems to produce a machine ora platform, such that the instructions, when executed via the processorof the computer or other programmable data processing devices, implementthe functions and/or steps specified in one or more flow charts and/orone or more block diagrams.

The computer-readable storage medium may refer to any type ofnon-transitory memory on which information or data readable by aprocessor may be stored. Thus, a computer-readable storage medium maystore instructions for execution by one or more processors, includinginstructions for causing the processor(s) to perform steps or stagesconsistent with the embodiments described herein. The computer-readablemedium includes non-volatile and volatile media, removable andnon-removable media. The information and/or data storage can beimplemented with any method or technology. Information and/or data maybe modules of computer-readable instructions, data structures, andprograms, or other types of data. Examples of a computer-readablestorage medium include, but are not limited to, a phase-change randomaccess memory (PRAM), a static random access memory (SRAM), a dynamicrandom access memory (DRAM), other types of random access memories(RAMs), a read-only memory (ROM), an electrically erasable programmableread-only memory (EEPROM), a flash memory or other memory technologies,a cache, a register, a compact disc read-only memory (CD-ROM), a digitalversatile disc (DVD) or other optical storage, a cassette tape, tape ordisk storage, or other magnetic storage devices, or any othernon-transitory media that may be used to store information capable ofbeing accessed by a computer device.

It should be noted that, the relational terms such as “first” and“second” are only used to distinguish an entity or operation fromanother entity or operation, and do necessarily require or imply thatany such actual relationship or order exists among these entities oroperations. It should be further noted that, as used in thisspecification and the appended claims, the singular forms “a,” “an,” and“the,” and any singular use of any word, include plural referents unlessexpressly and unequivocally limited to one referent. As used herein, theterms “include,” “comprise,” and their grammatical variants are intendedto be non-limiting, such that recitation of items in a list is not tothe exclusion of other like items that can be substituted or added tothe listed items. The term “if” may be construed as “at the time of,”“when,” “in response to,” or “in response to determining.”

Moreover, while illustrative embodiments have been described herein, thescope includes any and all embodiments having equivalent elements,modifications, omissions, combinations (e.g., of aspects across variousembodiments), adaptations or alterations based on the presentdisclosure. The elements in the claims are to be interpreted broadlybased on the language employed in the claims and not limited to examplesdescribed in the present specification or during the prosecution of theapplication, which examples are to be construed as non-exclusive.Further, the steps of the disclosed methods can be modified in anymanner, including by reordering steps or inserting or deleting steps. Itis intended, therefore, that the specification and examples beconsidered as example only, with a true scope and spirit being indicatedby the following claims and their full scope of equivalents.

This description and the accompanying drawings that illustrate exemplaryembodiments should not be taken as limiting. Various mechanical,compositional, structural, electrical, and operational changes may bemade without departing from the scope of this description and theclaims, including equivalents. In some instances, well-known structuresand techniques have not been shown or described in detail so as not toobscure the disclosure. Similar reference numbers in two or more figuresrepresent the same or similar elements. Furthermore, elements and theirassociated features that are disclosed in detail with reference to oneembodiment may, whenever practical, be included in other embodiments inwhich they are not specifically shown or described. For example, if anelement is described in detail with reference to one embodiment and isnot described with reference to a second embodiment, the element maynevertheless be claimed as included in the second embodiment.

Other embodiments will be apparent from consideration of thespecification and practice of the embodiments disclosed herein. It isintended that the specification and examples be considered as exampleonly, with a true scope and spirit of the disclosed embodiments beingindicated by the following claims.

What is claimed is:
 1. A method for switching a virtual internetprotocol (VIP) address, the method comprising: sending to a controlcenter of a VIP address system a first address resolution protocol (ARP)mapping message for mapping a VIP address to a VM address of a virtualmachine (VM) of the VIP address system having one or more VMs connectedto one or more virtual switches, the one or more VMs and one or morevirtual switches being located in one or more hosts that are connectedto the control center via a cloud network, wherein the VIP address isused by the control center to determine the VM corresponding to the VMaddress as the master VM; and sending a notification message to a VM inthe VIP address system, wherein the notification message is from thecontrol center determining the master VM.
 2. The method of claim 1, whenthe master VM is determined to be abnormal, further comprising:receiving a second ARP mapping message for mapping the VIP address tothe address of a backup VM from the backup VM, after the backup VMswitches its IP address to the VIP address; and sending the second ARPmapping message to the control center.
 3. The method of claim 1, furthercomprising: receiving a notification message sent by the control centerfor indicating an identifier of the master VM currently using the VIPaddress; and sending the notification message to a VM in the VIP addresssystem.
 4. The method of claim 3, further comprising: sending to thecontrol center a request message sent by a VM for acquiring theidentifier of the master VM; receiving a response message from thecontrol center carrying the identifier of the master VM; and sending theresponse message to a VM.
 5. The method of claim 1, further comprising:sending to the control center a request message sent by a backup VM foracquiring an association relationship between an identifier of thebackup VM and its priority level to become the master VM; receiving theassociation relationship from the control center; and sending theassociation relationship to the backup VM.
 6. The method of claim 5,further comprising: when the priority level of the backup VM is at ahighest priority level, detecting, at a set time interval, whether themaster VM is abnormal; and when the priority level of the backup VM isnot at the highest priority level, releasing network resources occupiedby the backup VM.
 7. The method of claim 1, further comprising:receiving a heartbeat message sent by a VM; and determining, based onthe heartbeat message, whether the VIP address has switched and whetherto send a second ARP mapping message to the control center.
 8. A methodfor switching a virtual internet protocol (VIP) address, the methodcomprising: receiving, from a virtual switch, a first ARP mappingmessage for mapping a VIP address to a virtual machine (VM) of a VIPaddress system using the VIP address, wherein the VIP address systemcomprises one or more VMs connected to one or more virtual switches, theone or more VMs and one or more virtual switches being located in one ormore hosts; determining the VM as the master VM based on the first ARPmapping message; and sending a notification message of determining themaster VM to a VM in the VIP address system via the virtual switchconnected to the VM.
 9. The method of claim 8, further comprising:receiving, via a virtual switch, a request message for acquiring anidentifier of the master VM from a VM; and sending, via the virtualswitch, to the VM a response message carrying the identifier of themaster VM based on the request message.
 10. The method of claim 8,further comprising: determining, based on the configuration of a VM inthe VIP address system, a priority level of the VM to become the masterVM; and storing an association relationship between an identifier of theVM and the priority level.
 11. The method of claim 10, furthercomprising: receiving, via a virtual switch, from a backup VM a requestmessage for acquiring the association relationship; and sending, via thevirtual switch, the association relationship to the backup VM.
 12. Anon-transitory computer readable medium that stores a set ofinstructions that is executable by at least one processor of a server tocause the server to perform a method for switching a virtual internetprotocol (VIP) address, the method comprising: providing for sending toa control center of a VIP address system a first address resolutionprotocol (ARP) mapping message for mapping a VIP address to a VM addressof a virtual machine (VM) of the VIP address system having one or moreVMs connected to one or more virtual switches, the one or more VMs andone or more virtual switches being located in one or more hosts that areconnected to the control center via a cloud network, wherein the VIPaddress is used by the control center to determine the VM correspondingto the VM address as the master VM; and providing for sending anotification message to a VM in the VIP address system, wherein thenotification message is from the control center determining the masterVM.
 13. The medium of claim 12, wherein, when the master VM isdetermined to be abnormal, the set of instructions that is executable bythe at least one processor of the server to cause the server to furtherperform: acquiring a second ARP mapping message for mapping the VIPaddress to the address of a backup VM from the backup VM, after thebackup VM switches its IP address to the VIP address; and providing forsending the second ARP mapping message to the control center.
 14. Themedium of claim 12, wherein the set of instructions that is executableby the at least one processor of the server to cause the server tofurther perform: acquiring a notification message sent by the controlcenter for indicating an identifier of the master VM currently using theVIP address; and providing for sending the notification message to a VMin the VIP address system.
 15. The medium of claim 14, wherein the setof instructions that is executable by the at least one processor of theserver to cause the server to further perform: providing for sending tothe control center a request message sent by a VM for acquiring theidentifier of the master VM; acquiring a response message from thecontrol center carrying the identifier of the master VM; and providingfor sending the response message to a VM.
 16. The medium of claim 12,wherein the set of instructions that is executable by the at least oneprocessor of the server to cause the server to further perform:providing for sending to the control center a request message sent by abackup VM for acquiring an association relationship between anidentifier of the backup VM and its priority level to become the masterVM; acquiring the association relationship from the control center; andproviding for sending the association relationship to the backup VM. 17.The medium of claim 16, wherein the set of instructions that isexecutable by the at least one processor of the server to cause theserver to further perform: when the priority level of the backup VM isat a highest priority level, detecting, at a set time interval, whetherthe master VM is abnormal; and when the priority level of the backup VMis not at the highest priority level, releasing network resourcesoccupied by the backup VM.
 18. The medium of claim 12, wherein the setof instructions that is executable by the at least one processor of theserver to cause the server to further perform: acquiring a heartbeatmessage sent by a VM; and determining, based on the heartbeat message,whether the VIP address is switched and whether to send a second ARPmapping message to the control center.
 19. A non-transitory computerreadable medium that stores a set of instructions that is executable byat least one processor of a server to cause the server to perform amethod for switching a virtual internet protocol (VIP) address, themethod comprising: acquiring, from a virtual switch, a first ARP mappingmessage for mapping a VIP address to a virtual machine (VM) of a VIPaddress system using the VIP address, wherein the VIP address systemcomprises one or more VMs connected to one or more virtual switches, theone or more VMs and one or more virtual switches being located in one ormore hosts; determining the VM as the master VM based on the first ARPmapping message; and providing for sending a notification message ofdetermining the master VM to a VM in the VIP address system via thevirtual switch connected to the VM.
 20. The medium of claim 19, whereinthe set of instructions that is executable by the at least one processorof the server to cause the server to further perform: acquiring, via avirtual switch, a request message for acquiring an identifier of themaster VM from a VM; and providing for sending, via the virtual switch,to the VM a response message carrying the identifier of the master VMbased on the request message.
 21. The medium of claim 19, wherein theset of instructions that is executable by the at least one processor ofthe server to cause the server to further perform: determining, based onthe configuration of a VM in the VIP address system, a priority level ofthe VM to become the master VM; and storing an association relationshipbetween an identifier of the VM and the priority level.
 22. The mediumof claim 21, wherein the set of instructions that is executable by theat least one processor of the server to cause the server to furtherperform: acquiring, via a virtual switch, from a backup VM a requestmessage for acquiring the association relationship; and providing forsending, via the virtual switch, the association relationship to thebackup VM.
 23. A virtual Internet protocol (VIP) address switchingapparatus, the apparatus comprising: a first sending unit configured tosend a control center of a VIP address system a first address resolutionprotocol (ARP) mapping message for mapping a VIP address to a VM addressof a virtual machine (VM) of the VIP address system having one or moreVMs connected to one or more virtual switches, the one or more VMs andone or more virtual switches being located in one or more hosts that areconnected to the control center via a cloud network, wherein the VIPaddress is used by the control center to determine the VM correspondingto the VM address as the master VM; and a second sending unit configuredto send a notification message to a VM in the VIP address system,wherein the notification message is from the control center determiningthe master VM.
 24. The apparatus of claim 23, further comprising: afirst receiving unit configured to receive a second ARP mapping messagefor mapping the VIP address to the address of a backup VM from thebackup VM, after the backup VM switches its IP address to the VIPaddress; and a third sending unit configured to send the second ARPmapping message to the control center.
 25. The apparatus of claim 23,wherein the second sending unit comprises: a first receiving sub-unitconfigured to receive a notification message sent by the control centerfor indicating an identifier of the master VM currently using the VIPaddress; and a first sending sub-unit configured to send thenotification message to a VM in the VIP address system.
 26. Theapparatus of claim 25, further comprising: a fourth sending unitconfigured to send to the control center a request message sent by a VMfor acquiring the identifier of the master VM; a second receiving unitconfigured to receive a response message from the control centercarrying the identifier of the master VM; and a first replying unitconfigured to send the response message to a VM.
 27. The apparatus ofclaim 23, further comprising: a fifth sending unit configured to send tothe control center a request message sent by a backup VM for acquiringan association relationship between an identifier of the backup VM andits priority level to become the master VM; a third receiving unitconfigured to receive the association relationship from the controlcenter; and a sixth sending unit configured to send the associationrelationship to the backup VM.
 28. The apparatus of claim 27, whereinthe sixth sending unit is further configured to: when the priority levelof the backup VM is at a highest priority level, detect, at a set timeinterval, whether the master VM is abnormal; and when the priority levelof the backup VM is not at the highest priority level, release networkresources occupied by the backup VM.
 29. The apparatus of claim 23,further comprising: a fourth receiving unit configured to receive aheartbeat message sent by a VM; and a determining unit configured todetermine, based on the heartbeat message, whether the VIP address isswitched and whether to send a second ARP mapping message to the controlcenter.
 30. A virtual internet protocol (VIP) address switchingapparatus, the apparatus comprising: a first receiving unit configuredto receive, from a virtual switch, an ARP mapping message for mapping aVIP address to a VM using the VIP address; a first determining unitconfigured to determine the VM as the master VM based on the ARP mappingmessage; and a first sending unit configured to send a notificationmessage of determining the master VM to a VM in the VIP address systemvia the virtual switch connected to the VM.
 31. The apparatus of claim30, further comprising: a second receiving unit configured to receive,via a virtual switch, a request message for acquiring an identifier ofthe master VM from a VM; and a first replying unit configured to send,via the virtual switch, to the VM a response message carrying theidentifier of the master VM based on the request message.
 32. Theapparatus of claim 30, further comprising: a second determining unitconfigured to determine, based on the configuration of a VM in the VIPaddress system, a priority level of the VM to become the master VM; anda storing unit configured to store an association relationship betweenan identifier of the VM and the priority level.
 33. The apparatus ofclaim 32, further comprising: a third receiving unit configured toreceive, via a virtual switch, from a backup VM a request message foracquiring the association relationship; and a second replying unitconfigured to send, via the virtual switch, the association relationshipto the backup VM.
 34. A virtual internet protocol (VIP) address system,the system comprising: a control center, and at least one host connectedto the control center via a cloud network, the at least one host beingprovided with a virtual machine (VM) and a virtual switch connected tothe VM, wherein the virtual switch is configured to send to the controlcenter an address resolution protocol (ARP) mapping message for mappinga VIP address to a VM address of a VM; and wherein the control center isconfigured to receive the ARP mapping message from the virtual switch,determine, based on the ARP mapping message, the VM as the master VM,and send, via the virtual switch, the notification message ofdetermining the master VM to a VM in the VIP address system.